The present invention is directed to a device for forming batches of flat pieces with decreasing thickness, such as box blanks, which are delivered from a processing machine.
These flat pieces can be processed either manually or automatically. In the manual processing, an operator takes a first batch of flat pieces, which has already been counted by the machine processing them and then arranges them in a storage device. Then a second batch is placed head-to-tail on top of the first batch, in order to form an almost rectangular parallelipiped. The packet formed by these two batches are then tied up or bundled.
An automatic processing is performed by a device which is located between the machine processing the flat pieces and a tying or bundling unit. The automatic processing unit will transfer the batches into the store. Devices for automatically processing the batches are disclosed in Swiss Patent 572,433, which was the basis of U.S. Pat. No. 3,970,202; Swiss Patent 646,389, which was the basis of U.S. Pat. No. 4,474,521; and German Printed Application 28 27 540, which was the basis of U.S. Pat. No. 4,264,255. The disclosures of each of the three above-mentioned U.S. Patents is incorporated by reference thereto.
In U.S. Pat. No. 4,474,521, a device which suerimposes flat pieces with decreasing thickness in a head-to-tail arrangement of half packets is disclosed. This horizontal conveyance between the processing machine and the bundling unit is achieved by a set of grippers taking a half packet each in a continuous move in a non-stop production. During the transfer, every other gripper pivots through 180.degree. in order to form regular piles with two half packets superimposed in a head-to-tail relationship.
In U.S. Pat. No. 4,264,255, a device which assembles half batches of flat pieces with decreasing thickness by means of a horizontally pivotable table is disclosed. While one-half of a packet is loaded, the table then pivots so that the second half packet can be laid down head-to-tail on top of the first half to form the complete batch, which can then be discharged.
The advantage of these two devices is that they allow a continuous production and do not need an operator to transfer the batches from the processing machine to the tying or bundling unit. These devices have, nonetheless, various drawbacks. They are quite bulky and their installation is complicated and expensive and requires heavy mechanical strengths imposed by the inertia of their particular elements, as well as the number and dimension of the movable elements. In one of the above examples, the half packets are not necessarily positioned adequately with regard to each other and this creates additional difficulties during the bundling operation because of possible cutting of the edges of the flat pieces.